Soft-metal electromechanical component and method making same

ABSTRACT

A three dimensional soft magnetic metal mass suitable for milling is formed wrapping soft magnetic metal ribbon into a three dimensional shape and then applying adhesive to the three dimensional shape. The adhesive permeates the three dimensional shape. The adhesive is then cured. If the soft magnetic metal mass is made as a toroid, then it could be processed into an electromechanical component. The electromechanical component would then be suitable for use in very high frequency electric motors.

[0001] This application is a continuation-in-part of U.S. applicationSer. No. 10/458,944, filed Jun. 11, 2003 (now U.S. Pat. No. ______).

BACKGROUND OF THE INVENTION

[0002] Multi-pole rotating electromechanical devices, such as motors,generators, re-gen motors, alternators, brakes and magnetic bearings arecomprised of rotors and electro-mechanical components. AC motors rotateby producing a rotating magnetic field pattern in the electro-mechanicalcomponent that causes the rotor to follow the rotation of this fieldpattern. As the frequency varies, the speed of the rotor varies. Toincrease the speed of the motor, the frequency of the input source mustbe increased.

[0003] High frequency motors manufactured with the proper materials canbe very efficient. For certain applications, like electric or hybridcars, highly efficient electric motors are desirable.

[0004] The construction of electro-mechanical components for highfrequency electric motors and generators is problematic. Iron or steelcomponents are quite common in electric motors and generators. However,at high frequencies, such as those greater than 400 Hz, conventionaliron or steel components are no longer practical. The high frequency ofthe AC source increases the core losses of the iron or steel components,reducing the overall efficiency of the motor. Additionally, at very highfrequencies, the component may become extremely hot, cannot be cooled byany reasonably acceptable means and may cause motor failure.

[0005] For construction of electro-mechanical components used in highfrequency electric motors, ribbon made from soft magnetic materialprovides distinct advantages. Examples of soft magnetic ribbon materialswould be either 1) conventional material typically defined as 0.008″ andthicker, non grain oriented with a typical Si content of 3%+/− ½% or 2)alternate soft materials that are 0.007″ or thinner with Si content of3% to 7%, amorphous, or nanocrystalline alloys and other grain orientedor non grain oriented alloys. Some soft magnetic ribbon materialsexhibit inherent characteristics that make their use in high frequencyelectro-mechanical rotating devices highly desirable. Some soft magneticribbons are easy to magnetize and demagnetize, which means anelectro-mechanical component made with these metals would have low powerloss, low temperature rise at high frequency, extremely fastmagnetization and easy conversion of electrical to mechanical energy. Anelectro-mechanical component made of such an metal would generate lesscore losses and be able to operate at much higher frequencies, resultingin motors and generators of exceptional efficiency and power density.

[0006] Soft magnetic materials are commercially produced as ribbon orstrip. A preferred example of a soft magnetic metal ribbon is Metglas®,which is an amorphous material, manufactured by Honeywell, Inc. Softmagnetic metal ribbons are very thin and of varying width. Manufacturingcomponents of soft magnetic metal ribbon requires winding the softmagnetic ribbon into a shape and then heat processing the shape. Simplethree dimensional shapes, such as toroids, can currently be constructedfrom soft magnetic metal ribbon.

[0007] However electro-mechanical components are often not simple threedimensional shapes. The electro-mechanical component can have numerousslots for accommodating motor coils in a generally toroidal structure.

[0008] Attempts to create complex three dimensional configurations fromsoft magnetic metal ribbon have heretofore been commerciallyunsuccessful. Various manufacturing techniques have been attempted byindustry such as but not limited to: wire electrical dischargemachining, electrochemical creep grinding, conventional electricaldischarge machining, cutting, stamping, acid etching and fine blanking.None have proven satisfactory for reasons such as cost-effectiveness,manufacturing repeatability, or process cycle time.

[0009] This inability to fabricate complex three dimensional shapes fromsoft magnetic ribbon has been the significant impediment to producinghigh efficiency axial flux motors and generators. A method to produceelectro-mechanical components from soft magnetic ribbon in a costeffective, end use functional, high volume capable method that will alsoprovide substantial design flexibility for end use requirements ishighly desirable.

SUMMARY OF THE INVENTION

[0010] A method for forming a three dimensional soft magnetic metal masssuitable for milling consists of wrapping soft magnetic metal ribboninto a three dimensional shape, then applying adhesive to the threedimensional shape. The adhesive is then cured and the cured form ismechanically constrained in three dimensions. The method results in softmagnetic metal mass which can withstand the mechanical stresses ofmachining. The three dimensional soft magnetic metal form can be milledusing a horizontal mill, a vertical mill, a computer numeric control(CNC) machine, or any other common milling equipment. Thus, complexthree dimensional soft magnetic metal shapes can be created.

[0011] The ability to create three dimensional soft magnetic metalshapes allows the use of soft magnetic metal for a variety ofapplications heretofore foreclosed by the mechanical characteristics ofsoft magnetic metal ribbon.

[0012] To manufacture an soft magnetic electro-mechanical component,soft magnetic metal ribbon is wound into a toroid. The toroid is thenplaced in a milling assembly. Adhesive is applied to the toroid, andthen cured. The toroid is then milled into an electro-mechanicalcomponent shape, and then thermally processed into a electro-mechanicalcomponent.

[0013] These and other objects, advantages and features of the inventionwill be more readily understood and appreciated by reference to thedetailed description of the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 shows a soft magnetic metal ribbon being wound on an innerring.

[0015]FIG. 2 shows an inner containment hat.

[0016]FIG. 3 shows an outer containment hat.

[0017]FIG. 4 shows a milling assembly.

[0018]FIG. 5 shows a milling assembly being milled.

[0019]FIG. 6 shows a soft magnetic metal electro-mechanical component.

DETAILED DESCRIPTION OF THE DRAWINGS

[0020]FIG. 1 shows soft magnetic metal ribbon 10 being wound about awinding axis 11 on an inner ring 14. Winding machine 13 contains softmagnetic metal ribbon roll 12. Inner ring 14 is placed on winding plate16. Soft magnetic metal ribbon 10 is wound on inner ring 14, formingsoft magnetic metal toroid 18. Soft magnetic metal toroid 18 has aninner side surface 15, an outer side surface 17, a top 19, and a bottom21.

[0021] While FIG. 1 shows the formation of an soft magnetic metal toroid18, it will be appreciated that a three dimensional shape could becreated with a geometry distinctly different from the soft magneticmetal toroid 18. For example, it would be possible by winding aroundfour corners to create a rectangular prism.

[0022] Soft magnetic metal ribbon 10 can be wound using a variety ofmachines and methods. Preferably, a consistent, firm toroid will have atleast an 85% wind density compared to the inherent ribbon density. Softmagnetic metal toroid 18 is then removed from winding plate 16. Softmagnetic metal ribbon 10 can be wound around the inner ring 14 whileattached to the inner containment hat 20 as a single unit.

[0023] An adhesive is then applied to the soft magnetic ribbon toroid 18in a manner to permeate the soft magnetic metal toroid 18. Inner ring 14is still contained within the soft magnetic ribbon toroid 18. A suitableadhesive is Scotch Cast adhesive by 3M, diluted by acetone so as toachieve about a 20% mix by volume. The adhesive is applied to softmagnetic ribbon toroid 18 by an ambient atmospheric soak process. Softmagnetic ribbon toroid 18 is immersed in the adhesive until the adhesiveinfiltrates the layers.

[0024] Alternatively, the adhesive could be applied by immersing softmagnetic ribbon toroid 18 into the adhesive inside a vessel that isevacuated of air. The vacuum created would enhance the infiltration ofthe adhesive into the soft magnetic ribbon toroid 18 layers. Adhesivecould also be applied to the soft magnetic ribbon during the windingprocess utilizing a wet spray or dry electrolytic deposition process.Alternative resins, epoxies or adhesives may be used. Different brandsas well as different types of resins, epoxies or adhesives may be used.Heat cured epoxies that require various temperatures as well a two stageepoxies that cure at room temperature would also be suitable.

[0025] After soft magnetic ribbon toroid 18 is sufficiently infiltratedwith adhesive, soft magnetic ribbon toroid 18 is allowed to drain. Oncedry, soft magnetic ribbon toroid 18 is placed inside an oven for curing.Importantly, the temperature for heat treating the adhesive be afraction of the temperature for heat processing soft magnetic metalribbon 10. A preferable fraction is ½, although fractions of ¼ and ¾might also be satisfactory.

[0026]FIG. 2 shows inner containment hat 20. Inner containment hat 20 isa cylinder comprised of a number of columns 22 extending upward from theinner containment hat base 24. Fingers 26 extend outward from columns 22at approximately a right angle. Fingers 26 increase in width as theyextend further from the columns 22. Fingers 26 are arranged in a circle,forming an annulus 28. The columns 22 and fingers 26 form a plurality ofinner containment hat grooves 29. Columns 22 of inner containment hat 20are placed inside inner ring 14.

[0027] The height of columns 22 is approximately equal to the height ofthe soft magnetic metal toroid 18. The diameter of the soft magneticmetal toroid 18 is about equal to the diameter of the annulus 28.

[0028] Following the placement of inner containment hat within softmagnetic metal toroid 18, outer containment hat 30 shown in FIG. 3, isplaced around soft magnetic metal toroid 18.

[0029] Outer containment hat 30 is cylindrical, with a base 32. Bars 34extend upward from base 32. At the top of each bar 34 is a lug 36extending inward. Lug 36 for each bar 34 forms a flange for securing theamorphous metal toroid 18 within outer containment hat 30. Bars 34 andlugs 36 form a plurality of outer containment hat grooves 38.

[0030] Milling assembly 40, shown in FIG. 4, is then formed. Softmagnetic metal toroid 18, still containing inner ring 14, along with theinner containment hat 20 is placed within outer containment hat 30. Lugs36 and fingers 26 are aligned. Milling assembly 40 contains the softmagnetic metal toroid 18 within a toroidal geometry. Alternatively, softmagnetic metal toroid 18 could be placed within outer containment hat 30and inner containment hat 20 prior to treatment with the adhesive.

[0031] After application of the adhesive and placement within themechanical constraints of the inner ring 14, inner containment hat 20,and outer containment hat 30, the soft magnetic metal toroid 18 hassufficient structural integrity to withstand the stresses of milling.

[0032] Milling plate 44 is placed on the bottom of the soft magneticmetal toroid 18. Milling plate 44 could be the same as winding plate 16.

[0033] Soft magnetic metal toroid 18, having been treated with anadhesive, is thus firmly contained within a structure, allowing softmagnetic metal toroid 18 to be milled and formed in three dimensions.Complex shapes can thus be constructed from the metal ribbon toroid 18,allowing structures such as electro-mechanical components to be madefrom the soft magnetic metal toroid 18.

[0034] As illustrated by FIG. 5, milling assembly 40 is placed in mill50. Mill 50 could be a horizontal mill, a vertical mill, a CNC machine,or any other type of mill. However, mill 50 should preferably have theaxis of rotation of the mill tools 52 perpendicular to the axis of thesoft magnetic metal toroid 18. By having the axis of rotation of themill tool 52 perpendicular to the axis of the soft magnetic metal toroid18, the depth and width of the slots milled into the soft magnetic metaltoroid 18 can be finely controlled.

[0035] Mill 50 cuts slots or other geometries into the soft magneticmetal toroid 18. Inner ring 14, still contained within soft magneticmetal toroid 18, acts as a positive mechanical stop for the inside edgeof soft magnetic metal toroid 18. Inner ring 14, in conjunction with theepoxy, does not allow strips of soft magnetic metal ribbon 10 toseparate during machining, thereby producing clean and accurate cuts.

[0036] After the soft magnetic metal toroid 18 is milled into anelectromechanical component shape, milling assembly 40 is removed frommill 50. Milling assembly 50 is then thermally processed in accordancewith the recommendations of the manufacturer of soft magnetic metalribbon 10 as required. If the amorphous metal ribbon 10 is Metglas®,thermal processing consists of placing milling assembly 50 into a vacuumfurnace at 695 degrees Fahrenheit for approximately sixty minutes. Somesoft magnetic ribbon materials require thermal processing to achieve thedesired magnetic properties while others require thermal processing toproperly relieve the stresses in the milled electro-mechanical componentshape as a result of the milling process. It is conceivable that, givenproper mechanical containment during milling, some materials that do notrequire thermal processing for magnetic properties could forego thethermal processing.

[0037] Following thermal processing, the milling assembly 40 isdisassembled by removing retainer 42, outer containment 30, innercontainment hat 20, and inner ring 14. Soft magnetic metal toroid 18 hasthus been made into an soft magnetic metal electromechanical component60, shown in FIG. 6.

[0038] The method as described allows for the creation of threedimensional forms from soft magnetic metal ribbon. The applications forsuch three dimensional forms could be as electromechanical componentsfor a variety of machines.

[0039] The above description is of the preferred embodiment. Variousalterations and changes can be made without departing from the spiritand broader aspects of the invention as defined in the appended claims,which are to be interpreted in accordance with the principles of patentlaw including the doctrine of equivalents. Any references to claimelements in the singular, for example, using the articles “a,” “an,”“the,” or “said,” is not to be construed as limiting the element to thesingular.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A method for forming athree dimensional soft magnetic metal mass suitable for milling,comprising the steps of: wrapping a soft magnetic metal ribbon into athree dimensional shape; applying an adhesive to the three dimensionalshape to allow permeation of the adhesive into the three dimensionalshape; and curing the adhesive.
 2. The method of claim 1 where the stepof applying an adhesive to the three dimensional shape comprises anambient atmospheric soak process.
 3. The method of claim 1 where thestep of applying the adhesive comprises a wet spray process appliedduring winding.
 4. The method of claim 1 where the step of applying theadhesive comprises an electrolytic deposition process during winding. 5.The method of claim 1 where the step of applying an adhesive to thethree dimensional shape comprises: providing a vessel containingadhesive; immersing the three dimensional shape in the adhesive; andevacuating the vessel.
 6. The method of claim 2 or 5 where the step ofcuring the adhesive comprises the step of heat treating the threedimensional shape.
 7. The method of claim 6 where the soft magneticmetal ribbon has a thermal processing temperature, and the step of heattreating the three dimensional shape occurs at a heat treatingtemperature, and the heat treating temperature is a fraction of thethermal processing temperature.
 8. The method of claim 7 where thefraction is about ½.
 9. The method of claim 7 where the fraction isabout ¾.
 10. The method of claim 7 where the fraction is about {fraction(1/)}.
 11. A three-dimensional soft magnetic metal mass suitable formilling made in accordance with claim
 1. 12. A method for forming a softmagnetic metal toroid suitable for milling comprising the steps: windinga soft magnetic metal ribbon into a toroid; applying an adhesive to thetoroid; and curing the adhesive.
 13. The method of claim 10 where thestep of applying an adhesive to the soft magnetic metal toroid comprisesan ambient atmospheric soak process.
 14. The method of claim 12 wherethe step of applying an adhesive to the soft magnetic metal toroidcomprises: providing a vessel containing adhesive; immersing the softmagnetic metal toroid in the adhesive; and evacuating the vessel. 15.The method of claim 13 or 14 where the step of curing the adhesiveincludes a step of heat treating the toroid.
 16. The method of claim 12where the soft magnetic metal ribbon has a thermal processingtemperature, and the step of heat treating the toroid occurs at a heattreating temperature, and the heat treating temperature is a fraction ofthe thermal processing temperature.
 17. The method of claim 16 where thefraction is about ½.
 18. The method of claim 16 where the fraction isabout ¾.
 19. The method of claim 16 where the fraction is about ¼.
 20. Amethod for manufacturing a soft magnetic metal electro-mechanicalcomponent comprising the steps of: winding soft magnetic metal ribboninto a toroid; containing the toroid within a toroidal geometry; millingthe toroid into a electro-mechanical component shape; and thermallyprocessing the electro-mechanical component shape into aelectro-mechanical component.
 21. The method of claim 20 where the stepof containing the toroid within a toroidal geometry comprises the stepsof: applying an adhesive to the toroid; and curing the adhesive.
 22. Themethod of claim 21 where the step of applying the adhesive to the toroidcomprises an atmospheric soak process.
 23. The method of claim 21 wherethe step of applying adhesive to the toroid includes the steps of:providing a vessel containing the adhesive; immersing the toroid in theadhesive; and evacuating the vessel.
 24. The method of claim 22 or 23including a step of curing the adhesive.
 25. The method of claim 24where the step of curing the adhesive at a heat treating temperature andthe step of thermally processing the electro-mechanical component shapeoccurs at a thermal processing temperature, and where the heat treatingtemperature is a fraction of the heat processing temperature.
 26. Themethod of claim 25 where the fraction is about ½.
 27. The method ofclaim 25 where the fraction is about ¾.
 28. The method of claim 25 wherethe fraction is about ¼.
 29. The method of claim 20 where the toroid hasa ribbon winding axis, and the step of milling the toroid into anelectro-mechanical component shape comprises milling the toroid with thecutting tool rotating in an axis perpendicular to the winding axis. 30.The method of claim 20 where the toroid has a ribbon winding axis, andthe step of milling the toroid into an electro-mechanical componentshape consists of milling the toroid with the cutting tool rotatingexclusively in an axis perpendicular to the ribbon winding axis.
 31. Anelectro-mechanical component made in accordance with claim
 20. 32. Amethod for manufacturing a soft magnetic metal electro-mechanicalcomponent comprising the steps of: winding soft magnetic metal ribboninto a toroid; containing the toroid within a milling assembly; applyingan adhesive to the toroid; curing the adhesive; milling the toroid intoan electro-mechanical component shape; and thermally processing theelectro-mechanical component shape into an electro-mechanical component.33. The method of claim 32 including the step of: removing the toroidfrom the milling assembly.
 34. The method of claim 32 where the toroidhas an inner side surface, an outer side surface, a top and a bottom.35. The method of claim 34 where the step of containing the toroidwithin a milling assembly comprises placing an inner ringcircumferentially about at least a portion of the inner side surface.36. The method of claim 34 where the step of containing the toroidwithin a milling assembly comprises placing an outer ringcircumferentially about at least a portion of the outer side surface.37. The method of claim 34 where the step of containing the toroidwithin a milling assembly comprises placing a hat on at least a portionof the top.
 38. The method of claim 34 where the step of containing thetoroid within a milling assembly comprises placing a base on at least aportion of the bottom.
 39. The method of claim 34 where the step ofcontaining the toroid within a milling assembly comprises the steps of:placing an inner ring circumferentially about at least a portion of theinner side surface; placing an outer ring circumferentially about atleast a portion of the outer side surface; and placing a hat on at leasta portion of the top.
 40. The method of claim 39 where the inner ring isplaced about substantially all of the inner side surface.
 41. The methodof claim 39 where the outer ring is placed about substantially all ofthe outer side surface.
 42. The method of claim 39 where the hat isplaced about substantially all of the top.
 43. The method of claim 39where a milling plate is placed about substantially all of the bottom.44. The method of claim 39 where the hat and the outer ring areintegral.
 45. The method of claim 39 where the hat, outer ring and innerring are integral.
 46. The method of claim 39 including the step ofplacing a retainer around the outer ring to secure the toroid within themilling assembly.
 47. The method of claim 40 including the step ofproviding milling grooves within the milling assembly.
 48. The method ofclaim 32 where the toroid has a ribbon winding axis, and the step ofmilling the toroid into a toroid shape consists of milling the toroidprimarily in an axis perpendicular to the winding axis.
 49. The methodof claim 32 where the toroid has a winding axis, and the step of millingthe toroid into a toroid shape consists of milling the toroidexclusively in an axis perpendicular to the winding axis.
 50. The methodof claim 45 where the toroid has a winding axis, and the step of millingthe toroid into a toroid shape consists of milling the toroid primarilyin an axis perpendicular to the winding axis.
 51. The method of claim 45where the hat and outer ring have slots, and the step of milling thetoroid into an electro-mechanical component shape includes millingthrough the slots.
 52. The method of claim 45 where the toroid has awinding axis, and the step of milling the toroid into anelectro-mechanical component shape consists of milling the toroid withthe cutting tool rotating exclusively in an axis perpendicular to thewinding axis.
 53. The method of claim 50 where the where the hat andouter ring have slots, and the step of milling the toroid into anelectro-mechanical component shape includes milling through the slots.54. A soft magnetic metal electro-mechanical component made from theprocess of claim
 32. 55. A method for manufacturing a soft magneticmetal electro-mechanical component comprising the steps of: winding softmagnetic metal ribbon about a winding axis into a toroid, the toroidhaving an inner side, an outer side, a top and a bottom; placing aninner ring on the inner side; placing an inner containment hat on thetop and inner side; placing an outer containment hat on the top andouter side; placing a retainer around the outer containment hat;applying adhesive to the toroid; curing the adhesive; milling the toroidinto an electromechanical component shape; and thermally processing theelectromechanical component shape into an electro-mechanical component.56. The method of claim 55 where the inner containment hat has aplurality of inner containment hat slots and the outer containment hathas a plurality of outer containment hat slots, and the step of millingthe toroid into a electromechanical component shape comprises millingthrough the inner containment hat slots and the outer containment hatslots.
 57. The method of claim 56 including a step of aligning the innercontainment hat slots and the outer containment hat slots.
 58. Themethod of claim 55 where the step of milling the toroid into anelectro-mechanical component shape occurs with the cutting toolsrotating primarily on an axis perpendicular to the winding axis.
 59. Themethod of claim 55 where the step of milling the toroid into anelectro-mechanical component shape occurs with the cutting toolsrotating exclusively on an axis perpendicular to the winding axis.